Liquid crystal display device and electronic apparatus

ABSTRACT

According to an aspect, a liquid crystal display device includes a first substrate, a second substrate, a liquid crystal layer, a first electrode, and a second electrode. The first electrode includes an electrode base portion extending in a first direction, and a plurality of comb tooth portions extending in a second direction different from the first direction and protruding from the electrode base portion with a certain distance interposed therebetween. At least one of the first substrate and the second substrate includes a light-blocking part that reduces intensity of light passing therethrough at a position overlapping with at least one of the center of the comb tooth portion and the center between the adjacent comb tooth portions in a direction perpendicular to the first substrate.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application claims priority to Japanese Priority PatentApplication JP 2014-098531 filed in the Japan Patent Office on May 12,2014, the entire content of which is hereby incorporated by reference.

BACKGROUND

1. Technical Field

The present invention relates to a liquid-crystal display deviceprovided with liquid crystals and to an electronic apparatus includingthe liquid-crystal display device provided with liquid crystals.

2. Description of the Related Art

There have been developed systems (modes) for driving liquid crystals,including a liquid crystal driving system that uses an electric fieldgenerated in a vertical direction between substrates, that is, avertical electric field. Examples of a liquid crystal display devicethat drives liquid crystals using a vertical electric field include, butare not limited to, vertical-electric-field liquid crystal displaydevices provided with a twisted nematic (TN) system, a verticalalignment (VA) system, an electrically controlled birefringence (ECB)system, etc. As disclosed in Japanese Patent Application Laid-openPublication No. 2008-52161 (JP-A-2008-52161), there has also beendeveloped a liquid crystal driving system that uses an electric fieldgenerated in a direction parallel to substrates (horizontal direction),that is, a horizontal electric field. Examples of a liquid crystaldisplay device that drives liquid crystals using a horizontal electricfield include, but are not limited to, horizontal-electric-field liquidcrystal display devices provided with a fringe field switching (FFS)system, an in-plane switching (IPS) system, etc.

In the IPS mode, a first electrode and a second electrode are providedon the same layer, and an electric field is generated mainly in adirection parallel to the substrate surface. This configuration makes itdifficult for the electric field to be generated in an area on the firstelectrode, thereby making it difficult for liquid-crystal molecules inthe area to be driven.

In the FFS mode, a pixel electrode and a common electrode overlap in adirection perpendicular to the substrate surface with a dielectric filminterposed therebetween, and an electric field extending mainly in adirection oblique to the substrate surface or a parabolic electric field(also referred to as a fringe electric field) is generated. This makesit easy for liquid-crystal molecules in an area on the pixel electrodeto be driven. In other words, the FFS mode can provide a higher apertureratio than the IPS mode does.

The horizontal-electric-field liquid crystal display device generates anelectric field between the first electrode and the second electrode in adirection parallel to the substrate, thereby rotating the liquid crystalmolecules in a plane parallel to the substrate surface. The liquidcrystal display device uses a change in the light transmittancecorresponding to the rotation of the liquid crystal molecules, therebyperforming display. Such horizontal-electric-field liquid crystaldisplay devices are required to achieve a higher response speed of theliquid crystals.

Japanese Patent Application Laid-open Publication No. 2013-109309(JP-A-2013-109309) discloses a liquid crystal display device achieving ahigher response speed of liquid crystals.

In the liquid crystal display device disclosed in JP-A-2013-109309,although the response speed of the liquid crystals is improved in thewhole pixels, there is an area in which the liquid crystal moleculehardly move even when voltage is applied, and improvement in contrast isdesired.

For the foregoing reasons, there is a need for a liquid crystal displaydevice and an electronic apparatus that improve the contrast of entirepixels while improving the response speed of the entire pixels tofurther improve display quality in a plane.

SUMMARY

According to an aspect, a liquid crystal display device includes a firstsubstrate, a second substrate arranged to be opposed to the firstsubstrate, a liquid crystal layer arranged between the first substrateand the second substrate, a first electrode arranged between the firstsubstrate and the liquid crystal layer, and a second electrode arrangedat a position opposed to the first electrode. The first electrodeincludes an electrode base portion extending in a first direction, and aplurality of comb tooth portions extending in a second directiondifferent from the first direction and protruding from the electrodebase portion with a certain distance interposed therebetween. At leastone of the first substrate and the second substrate includes alight-blocking part that reduces intensity of light passing therethroughat a position overlapping with at least one of the center of the combtooth portion and the center between the adjacent comb tooth portions ina direction perpendicular to the first substrate.

According to another aspect, an electronic apparatus includes a liquidcrystal display device, and a control device that supplies input signalsto the liquid crystal display device. The liquid crystal display deviceincludes a first substrate, a second substrate arranged to be opposed tothe first substrate, a liquid crystal layer arranged between the firstsubstrate and the second substrate, a first electrode arranged betweenthe first substrate and the liquid crystal layer; and a second electrodearranged at a position opposed to the first electrode. The firstelectrode includes an electrode base portion extending in a firstdirection, and a plurality of comb tooth portions extending in a seconddirection different from the first direction and protruding from theelectrode base portion with a certain distance interposed therebetween.At least one of the first substrate and the second substrate includes alight-blocking part that reduces intensity of light passing therethroughat a position overlapping with at least one of the center of the combtooth portion and the center between the adjacent comb tooth portions ina direction perpendicular to the first substrate.

Additional features and advantages are described herein, and will beapparent from the following Detailed Description and the figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a block diagram illustrating a system configuration example ofa liquid crystal display device according to an embodiment;

FIG. 2 is a circuit diagram illustrating a drive circuit that drivespixels in the liquid crystal display device according to the embodiment;

FIG. 3 is a plan view for explaining the pixels in the liquid crystaldisplay device according to the embodiment;

FIG. 4 is a schematic diagram illustrating a sectional view along theline A1-A2 of FIG. 3;

FIG. 5 is a schematic diagram for explaining a relation between a shapeof a first electrode and an aperture according to the embodiment;

FIG. 6 is a schematic diagram for explaining a relation between theshape of the first electrode and a shaded position according to theembodiment;

FIG. 7 is an explanatory diagram for explaining orientation of liquidcrystals in a state where no voltage to generate an electric fieldbetween the first electrode and a second electrode is applied in theliquid crystal display device according to the embodiment;

FIG. 8 is a schematic diagram illustrating a sectional view along theline B1-B2 of FIG. 7;

FIG. 9 is an explanatory diagram for explaining orientation of theliquid crystals in a state where the voltage to generate an electricfield between the first electrode and the second electrode is applied inthe liquid crystal display device according to the embodiment;

FIG. 10 is a schematic diagram illustrating a sectional view along theline C1-C2 of FIG. 9;

FIG. 11 is a schematic diagram for explaining in detail the shape of thefirst electrode in the pixel according to the embodiment;

FIG. 12 is a schematic diagram for explaining in detail a transmissionineffective area according to the embodiment;

FIG. 13 is a schematic diagram illustrating a disclination line of thefirst electrode according to the embodiment;

FIG. 14 is a schematic diagram for explaining in detail a transmissionineffective area according to a first modification of the embodiment;

FIG. 15 is a schematic diagram illustrating a disclination line of afirst electrode according to the first modification of the embodiment;

FIG. 16 is an explanatory diagram illustrating light transmittancedistribution due to a disclination line of a first electrode accordingto a comparative example;

FIG. 17 is an explanatory diagram illustrating a positional relationbetween light transmittance distribution due to the disclination line ofthe first electrode according to the embodiment and a light-blockingpart;

FIG. 18 is a schematic diagram illustrating a modification of thesectional view along the line A1-A2 of FIG. 3 in the liquid crystaldisplay device according to a second modification of the embodiment;

FIG. 19 is a schematic diagram for explaining a modification of arelation between the shape of the first electrode and the aperture in aliquid crystal display device according to a third modification of theembodiment;

FIG. 20 is a plan view for explaining a pixel in a liquid crystaldisplay device according to a fourth modification of the embodiment;

FIG. 21 is a schematic diagram illustrating a sectional view along theline E1-E2 of FIG. 20;

FIG. 22 is an explanatory diagram for explaining a relation between aresponse speed of a pixel and an average interval between disclinationlines in a first evaluation example of the liquid crystal display unitaccording to the embodiment;

FIG. 23 is an explanatory diagram for explaining a relation between aresponse speed of a pixel and an average transmission effective intervalin a second evaluation example of the liquid crystal display unitaccording to the embodiment;

FIG. 24 is a diagram illustrating an example of an electronic apparatusto which the liquid crystal display device according to the embodimentis applied; and

FIG. 25 is a diagram illustrating an example of the electronic apparatusto which the liquid crystal display device according to the embodimentis applied.

DETAILED DESCRIPTION

Exemplary embodiments according to the present invention are describedbelow in greater detail with reference to the accompanying drawings. Thecontents described in the embodiments are not intended to limit thepresent invention. Components described below include components easilyconceivable by those skilled in the art and components substantiallyidentical therewith. Furthermore, the components described below can beappropriately combined. The disclosure is given by way of example only.Various changes and modifications made without departing from the spiritof the present invention and easily conceivable by those skilled in theart are naturally included in the scope of the present invention. Thedrawings may possibly illustrate the width, the thickness, the shape,and the like of each unit more schematically than the actual aspect tosimplify the explanation. These elements, however, are given by way ofexample only and are not intended to limit interpretation of theinvention. In the specification and the figures, components similar tothose previously described with reference to a preceding figure aredenoted by like reference numerals, and overlapping explanation thereofwill be appropriately omitted.

FIG. 1 is a block diagram of an exemplary system configuration of aliquid-crystal display device according to the embodiment. Aliquid-crystal display device 1 is a transmissive liquid-crystal displaydevice and includes a display panel 2 and a driver IC 3. Flexibleprinted circuits (FPCs), which are not illustrated, transmit an externalsignal to the driver IC 3 or drive electric power for driving the driverIC 3. The display panel 2 includes a translucent insulation substratesuch as a glass substrate 11, a display area 21, a horizontal driver (ahorizontal drive circuit) 23, and a vertical driver (a vertical drivecircuit) 22. The display area 21 is provided on the surface of the glasssubstrate 11 and is formed of a number of pixels each including aliquid-crystal cell arranged in a matrix (rows and columns). The glasssubstrate 11 includes a first substrate and a second substrate. In thefirst substrate, a number of pixel circuits each including an activeelement (e.g., a transistor) are arranged in a matrix. The secondsubstrate is arranged facing the first substrate with a certain gapinterposed therebetween. The gap between the first substrate and thesecond substrate is maintained to the certain gap by photo spacersarranged at respective positions on the first substrate. The gap betweenthe first substrate and the second substrate is sealed with liquidcrystals.

Exemplary system configuration of the liquid-crystal display device

The display panel 2 includes the display area 21, the driver IC 3 havingfunctions of an interface (I/F) and a timing generator, the verticaldriver 22, and the horizontal driver 23 on the glass substrate 11.

In the display area 21, sub-pixels Vpix that include the liquid crystallayer have a matrix (row-and column) structure in which units eachforming one pixel on display are arranged in m rows×n columns. In thepresent specification, a row indicates a pixel row including Nsub-pixels Vpix arrayed in a direction. A column indicates a pixelcolumn including M sub-pixels Vpix arrayed in a direction orthogonal tothe direction in which the sub-pixels Vpix included in the row arearrayed. The values of M and N are determined depending on displayresolution in the vertical direction and that in the horizontaldirection, respectively. In the display area 21, with respect to thearray of M-by-N sub-pixels Vpix, scanning lines 24 ₁, 24 ₂, 24 ₃ . . .24 _(M) are arranged for each row and signal lines 25 ₁, 25 ₂, 25 ₃ . .. 25 _(N) are arranged for each column. In the embodiment, the scanninglines 24 ₁, 24 ₂, 24 ₃ . . . 24 _(M) may be collectively referred to asa scanning line 24, whereas the signal lines 25 ₁, 25 ₂, 25 ₃ . . . 25_(N) may be collectively referred to as a signal line 25. In theembodiment, any scanning line of the scanning lines 24 ₁, 24 ₂, 24 ₃ . .. 24 _(M) may be expressed as a scanning line 24 _(α+1) (0≦α≦M), whereasany signal line of the signal lines 25 ₁, 25 ₂, 25 ₃ . . . 25 _(N) maybe expressed as a signal line 25 _(β+1) (0≦β≧N).

The liquid crystal display device 1 receives a master clock, ahorizontal synchronizing signal, and a vertical synchronizing signal,which are external signals from the outside. These signals are suppliedto the driver IC 3. The driver IC 3 converts the level of the masterclock, the horizontal synchronizing signal, and the verticalsynchronizing signal at voltage amplitude of an external power sourceinto a level at voltage amplitude of an internal power source requiredfor driving the liquid crystals. Thus, the driver IC 3 generates amaster clock, a horizontal synchronizing signal, and a verticalsynchronizing signal. The driver IC 3 supplies the generated masterclock, the generated vertical synchronizing signal, and the generatedhorizontal synchronizing signal to the vertical driver 22 and thehorizontal driver 23. The driver IC 3 generates a common potential to besupplied to pixels in common to a common electrode COM for eachsub-pixel Vpix, which will be described later, and supplies the commonpotential to the display area 21.

The vertical driver 22 sequentially samples and latches, in onehorizontal period, display data output from the driver IC 3 insynchronization with a vertical clock pulse. The vertical driver 22sequentially outputs and supplies the latched digital data of one lineas a vertical scanning pulse to the scanning lines 24 _(m), 24 _(m+1),24 _(m+2) . . . of the display area 21. Thus, the vertical driver 22sequentially selects sub-pixels Vpix row by row. The vertical driver 22,for example, outputs the digital data to the scanning lines 24 _(m), 24_(m+1), 24 _(m+2) . . . from the top of the display area 21, that is,the upper side in the vertical scanning, to the bottom of the displayarea 21, that is, the lower side in the vertical scanning.Alternatively, the vertical driver 22 may output the digital data to thescanning lines 24 _(m), 24 _(m+1), 24 _(m+2) . . . from the bottom ofthe display area 21, that is, the lower side in the vertical scanning,to the top of the display area 21, that is, the upper side in thevertical scanning in order.

The horizontal driver 23 is supplied with 6-bit digital video data Vsigof R (red), G (green), and B (blue), for example. The horizontal driver23 writes display data to the sub-pixels Vpix of the row selected in thevertical scanning performed by the vertical driver 22 in units of apixel, a plurality of pixels, or all the pixels via the signal line 25.

In the liquid crystal display device 1, continuous application of adirect current (DC) voltage with the same polarity to the liquid crystalelements may possibly deteriorate resistivity (resistance value specificto the substance) and the like of the liquid crystals. To suppressdeterioration in the resistivity (resistance value specific to thesubstance) and the like of the liquid crystals, the liquid crystaldisplay device 1 employs a driving method for reversing the polarity ofvideo signals at a certain period based on the common potential of drivesignals.

Some types of methods for driving a liquid crystal display panel areknown, including a line inversion driving method, a dot inversiondriving method, and a frame inversion driving method. The line inversiondriving method is a method for reversing the polarity of video signalsat a time period of 1H (H represents a horizontal period) correspondingto one line (one pixel row). The dot inversion driving method is amethod for alternately reversing the polarity of video signals forpixels vertically and horizontally adjacent to each other. The frameinversion driving method is a method for reversing the polarity of videosignals to be written to all the pixels in one frame corresponding toone screen with the same polarity at a time. The liquid crystal displaydevice 1 may employ any one of the driving methods described above.

FIG. 2 is a circuit diagram illustrating a drive circuit that drivespixels in the liquid crystal display device according to the embodiment.In the display area 21, wiring of the signal lines 25 _(n), 25 _(n+1),25 _(n+2) and the scanning lines 24 _(m), 24 _(m+1), 24 _(m+2) areformed, for example. The signal lines 25 _(n), 25 _(n+1), 25 _(n+2)supply pixel signals to thin film transistor (TFT) elements Tr inrespective sub-pixels Vpix as display data. The scanning lines 24 _(m),24 _(m+1), 24 _(m+2) drive respective TFT elements Tr. The signal lines25 _(n), 25 _(n±i), 25 _(n+2) extend on a plane parallel to the surfaceof the glass substrate 11 described above and supply the pixel signalsfor displaying an image on the sub-pixels Vpix. Each of the sub-pixelsVpix includes the TFT element Tr and a liquid crystal capacitor LC. TheTFT element Tr is formed of a thin film transistor, and specifically ofan n-channel metal oxide semiconductor (MOS) TFT in this example. One ofthe source and the drain of the TFT element Tr is coupled to thecorresponding one of the signal lines 25 _(n), 25 _(m+1), 25 _(m+2), thegate thereof is coupled to the corresponding one of the scanning lines24 _(m), 24 _(m+1), 24 _(m+2), and the other of the source and the drainthereof is coupled to one end of the liquid crystal capacitor LC. Theone end of the liquid crystal capacitor LC is coupled to the other ofthe source and the drain of the TFT element Tr, whereas the other endthereof is coupled to the corresponding common electrode COM.

The sub-pixel Vpix is coupled to other sub-pixels Vpix belonging to thesame row in the display area 21 by the corresponding one of the scanninglines 24 _(m), 24 _(m+1), 24 _(m+2). The scanning lines 24 _(m), 24_(m+1), 24 _(m+2) are coupled to the vertical driver 22 and are suppliedwith the vertical scanning pulses of scanning signals from the verticaldriver 22. The sub-pixel Vpix is further coupled to other sub-pixelsVpix belonging to the same column in the display area 21 by thecorresponding one of the signal lines 25 _(n), 25 _(m+1), 25 _(m−). Thesignal lines 25 _(n), 25 _(n+1), 25 _(n+2) are coupled to the horizontaldriver 23 and are supplied with pixel signals from the horizontal driver23. The sub-pixel Vpix is further coupled to the other sub-pixels Vpixbelonging to the same column in the display area 21 by the correspondingcommon electrode COM. The common electrodes COM are coupled to thedriver IC 3, and are supplied with drive signals from the driver IC 3.

The vertical driver 22 illustrated in FIG. 1 applies vertical scanningpulses to the gate of the TFT element Tr of the sub-pixels Vpix via thescanning lines 24 _(m), 24 _(m+1), 24 _(m+2) illustrated in FIG. 2.Thus, the vertical driver 22 sequentially selects a row (a horizontalline) out of the rows of the sub-pixels Vpix arranged in a matrix in thedisplay area 21 as a target of display drive. The horizontal driver 23illustrated in FIG. 1 supplies pixel signals to the respectivesub-pixels Vpix forming each horizontal line sequentially selected bythe vertical driver 22 via the corresponding one of the signal lines 25_(n), 25 _(n+1), 25 _(n+2) illustrated in FIG. 2. These sub-pixels Vpixperform display of the horizontal line in accordance with the suppliedpixel signals. The driver IC 3 applies drive signals, thereby drivingcommon electrodes COM in each drive electrode block including a certainnumber of common electrodes COM.

As described above, the vertical driver 22 in the liquid crystal displaydevice 1 performs driving so as to sequentially scan the scanning lines24 _(m), 24 _(m+1), 24 _(m+2), thereby sequentially selecting ahorizontal line. The horizontal driver 23 in the liquid crystal displaydevice 1 supplies the pixel signals to the sub-pixels Vpix belonging tothe horizontal line, thereby performing display of the horizontal line.In performing the display operation, the driver IC 3 applies the drivesignals to the common electrode COM corresponding to the horizontalline.

A control device 4 includes, for example, a central processing unit(CPU) 41 serving as an arithmetic unit and a storage device 42 servingas a memory, and can implement various functions by executing computerprograms using such hardware resources. Specifically, the control device4 reads out a computer program stored in the storage device 42 to beloaded on the memory, and causes the CPU 41 to execute a commandincluded in the computer program loaded on the memory. The controldevice 4 then performs control so that the driver IC 3 can handle animage to be displayed on the display panel 2 as information of imageinput gradation depending on a command execution result by the CPU 41. Abacklight 6 irradiates the display panel 2 with light according to acontrol signal of the control device 4, and allows light to be incidenton the entire surface of the display area 21. The backlight 6 includes,for example, a light source and a light guide plate that guides lightoutput from the light source to be emitted to the back surface of thedisplay panel 2. The backlight 6 includes a plurality of light sourcesarranged in a direction along one side of the display area 21, and anamount of light from each light source may be independently controlled.Accordingly, the backlight 6 can cause light to be incident on part ofthe display panel 2 due to the light emitted from only part of the lightsources. In the embodiment, the backlight 6 arranged on the back surfaceside of the display panel 2 is used as the light source of the liquidcrystal display device 1. Alternatively, the light source may be a frontlight arranged on the front surface side of the display panel 2.

The display area 21 includes a color filter. The color filter includes agrid-shaped black matrix 76 a and apertures 76 b. The black matrix 76 ais formed to cover the outer periphery of the sub-pixel Vpix asillustrated in FIG. 2. In other words, the black matrix 76 a is arrangedat a boundary between the sub-pixels Vpix that are two-dimensionallyarranged and thus is formed into a grid shape. The black matrix 76 a ismade of a material having a high light absorption rate. The aperture 76b serves as an aperture formed by the grid shape of the black matrix 76a and is arranged at a position corresponding to the sub-pixel Vpix. Asdescribed above, the black matrix 76 a is a light-blocking part (asecond light-blocking part) having a light blocking property thatsurrounds the aperture of the sub-pixel Vpix.

The aperture 76 b includes color areas colored with three colors of red(R), green (G), and blue (B), for example. In the color filter, thecolor areas of the color filter in the three colors of red (R), green(G), and blue (B) are periodically arrayed on the respective apertures76 b, for example. Thus, the color areas in the three colors of R, G,and B correspond to the respective sub-pixels Vpix illustrated in FIG. 2and serve as a pixel Pix as a set.

The color filter may be made by a combination of other colors as long asit is colored differently. Typically, the luminance of the color area ofgreen (G) is higher than that of the color areas of red (R) and blue(B). The display area may be provided with no color filter, resulting inproduction of white color. Alternatively, the color filter may be madeof a transmissive resin to produce a white color.

Viewed from a direction orthogonal to the front surface, the scanningline 24 and the signal line 25 in the display area 21 are arranged at anarea overlapping with the black matrix 76 a. In other words, thescanning line 24 and the signal line 25 are hidden behind the blackmatrix 76 a viewed from a direction orthogonal to the front surface. Asdescribed above, the black matrix 76 a is a light-blocking part (asecond light-blocking part) having a light blocking property arranged tobe opposed to the scanning line 24 or the signal line 25. The displayarea 21 has the aperture 76 b in each area in which no black matrix 76 ais arranged.

As illustrated in FIG. 2, the scanning lines 24 _(m), 24 _(m+1), 24_(m+2) are arranged at regular intervals, and the signal lines 25 _(n),25 _(n+1), 25 _(n+2) are also arranged at regular intervals. Adjacentscanning lines 24 do not necessarily have a regular intervaltherebetween, and adjacent signal lines 25 do not necessarily have aregular interval therebetween either. The sub-pixels Vpix are arrangedfacing each other in the same direction at the respective areassectioned by the proximate scanning lines 24 _(m), 24 _(m+1), 24 _(m+2)and the proximate signal lines 25 _(n), 25 _(n+1), 25 _(n+2).

FIG. 3 is a plan view for explaining the pixels in the liquid crystaldisplay device according to the embodiment. FIG. 4 is a schematicdiagram illustrating a sectional view along the line A1-A2 of FIG. 3. Asillustrated in FIGS. 3 and 4, in the embodiment, one direction along aplane of the liquid crystal display device 1 (the display panel 2illustrated in FIG. 1) is assumed to be an X-direction, a directionorthogonal to the X-direction is assumed to be a Y-direction, and adirection orthogonal to the X-Y plane is assumed to be a Z-direction. Ineach sub-pixel Vpix, the aperture 76 b is formed on the lower side inthe vertical scanning (lower side in FIG. 3). The TFT element Tr isarranged on the left on the upper side in the vertical scanning (upperside in FIG. 3). A contact 90H is formed on the right on the upper sidein the vertical scanning (upper side in FIG. 3). The contact 90H is usedto couple a pixel electrode to a drain electrode 90 of the TFT elementTr. The drain of the TFT element Tr includes part of a semiconductorlayer (an active layer) and the drain electrode 90. Similarly, thesource of the TFT electrode Tr includes another part of thesemiconductor layer (active layer) and a source electrode 91. Colorfilters 76R, 76G, and 76B are formed by periodically arraying the colorareas of the color filters in the three colors of red (R), green (G),and blue (B) on the respective apertures 76 b, for example. Thus, thecolor areas 49R, 49G, and 49B in the three colors of R, G, and Billustrated in FIG. 3 are formed in the respective sub-pixels Vpixillustrated in FIG. 2.

As illustrated in FIG. 4, the liquid crystal display device 1 includes apixel substrate (the first substrate) 70A, a counter substrate (thesecond substrate) 70B arranged facing the surface of the pixel substrate70A in a direction perpendicular thereto, and a liquid crystal layer 70Cinserted between the pixel substrate 70A and the counter substrate 70B.The surface of the pixel substrate 70A on the side opposite to theliquid crystal layer 70C is provided with the backlight 6. Photo spacers(not illustrated) maintain a gap between the pixel substrate 70A and thecounter substrate 70B to a certain gap.

In the embodiment, an electric field (a horizontal electric field) isgenerated between a first electrode 31 and a second electrode 32laminated in a direction (the Z-direction) perpendicular to the surfaceof a TFT substrate 71 of the pixel substrate 70A and in a directionparallel to the TFT substrate 71. As a result, the liquid crystalmolecules in the liquid crystal layer 70C rotate in a plane parallel tothe substrate surface. The liquid crystal display device 1 uses a changein the light transmittance corresponding to the rotation of the liquidcrystal molecules, thereby performing display. The second electrode 32illustrated in FIG. 4 is the pixel electrode, whereas the firstelectrode 31 is the common electrode COM, for example. As illustrated inFIG. 4, a first orientation film 73 a is provided between the liquidcrystal layer 70C and the pixel substrate 70A, whereas a secondorientation film 73 b is provided between the liquid crystal layer 70Cand the counter substrate 70B.

The counter substrate 70B includes a glass substrate 72 and thelight-blocking black matrix 76 a formed on one surface of the glasssubstrate 72. The black matrix 76 a faces the liquid crystal layer 70Cin a direction perpendicular to the pixel substrate 70A. In the liquidcrystal display device 1 according to the embodiment, the aperture 76 balso includes a light-blocking part 76 c having a light blockingproperty in the same layer as the black matrix 76 a. The light-blockingpart 76 c is in the same layer as the black matrix 76 a, and thereby canbe formed of the same material as the black matrix 76 a withoutadditional processes. A position of the light-blocking part 76 c will bedescribed later.

The pixel substrate 70A includes the TFT substrate 71 serving as acircuit substrate. The scanning line 24 _(m) illustrated in FIG. 3 isformed on the TFT substrate 71. A gate electrode 93 is electricallycoupled to the scanning line 24 _(m). While the scanning line 24 _(m)and the gate electrode 93 are formed in different layers in FIGS. 3 and4, the scanning line 24 _(m) and the gate electrode 93 may be integrallyformed.

A semiconductor layer 92 containing amorphous silicon (a-Si) forming theTFT element Tr is formed in an upper layer of the gate electrode 93. Thesemiconductor layer 92 is coupled to the source electrode 91 forming theTFT element Tr. The source electrode 91 is an electric conductor and iselectrically coupled to a part of the semiconductor layer 92. The sourceelectrode 91 is electrically coupled to the signal line 25 _(n)illustrated in FIG. 3 (not illustrated in FIG. 4). The semiconductorlayer 92 is coupled to the drain electrode 90 forming the TFT elementTr. The drain electrode 90 is electrically coupled to another part ofthe semiconductor layer 92. While the signal line 25 _(n) and the sourceelectrode 91 are formed in different layers in FIG. 3, the signal line25 _(n) and the source electrode 91 may be integrally formed. Thesemiconductor layer 92 may contain LTPS (Low temperature Polysilicon) oroxide instead of amorphous silicon.

In the liquid crystal display device 1 according to the embodiment, theaperture 76 b also includes therein a light-blocking part 76 d having alight blocking property in the same layer as the source electrode 91 orthe drain electrode 90. The light-blocking part 76 d is included in thepixel substrate 70A. A material of the light-blocking part 76 d is thesame as that of the source electrode 91 or the drain electrode 90 thatis wiring for causing the first electrode 31 or the second electrode 32to work. Due to this, a forming pattern of the light-blocking part 76 dhas high accuracy, and additional processes are not required. A positionof the light-blocking part 76 d will be described later. The liquidcrystal display device 1 according to the embodiment may include atleast one of the light-blocking part 76 c and the light-blocking part 76d illustrated in FIG. 4.

An insulation layer 74 is formed of laminated insulation films, whichare an insulation film 741 between the scanning line 24 _(m) and thesemiconductor layer 92, an insulation film 742 between the semiconductorlayer 92 and the signal line 25 _(n), an insulation film 743 between thesignal line 25 _(n) and the second electrode 32, and an insulation film744 between the second electrode 32 and the first electrode 31, forexample. The insulation films 741, 742, 743, and 744 may be made of thesame insulation material, or any one thereof may be made of a differentinsulation material. For example, the insulation film 743 is made of anorganic insulation material such as a polyimide resin and the otherinsulation films (insulation films 741, 742, and 744) are made of aninorganic insulation material such as silicon nitride and silicon oxide.

The contact 90H made of a conductive metal is formed in what is called acontact hole. The contact 90H couples the drain electrode 90 and thesecond electrode 32. The first electrode 31 serves as the commonelectrode COM and is supplied with a common potential to be supplied tothe pixels in common. The first electrode 31 and the second electrode 32are translucent electrodes made of a translucent conductive material (atranslucent conductive oxide) such as indium tin oxide (ITO).

FIG. 5 is a schematic diagram for explaining a relation between theshape of the first electrode and the aperture according to theembodiment. As illustrated in FIG. 5, the first electrode 31 has a combteeth shape formed by slits S that are areas with no conductive materialprovided. The first electrode 31 includes a plurality of comb toothportions 131 protruding from an electrode base portion 132 extending inthe Y-direction. The comb tooth portions 131 include comb tooth portions131 a and comb tooth portions 131 b. The comb tooth portions 131 a andthe comb tooth portions 131 b extend in opposite directions from theelectrode base portion 132. The comb tooth portions 131 a protrude fromthe electrode base portion 132 with a certain distance interposedtherebetween. Similarly, the comb tooth portions 131 b protrude from theelectrode base portion 132 with a certain distance interposedtherebetween. From each electrode base portion 132, the comb toothportions 131 a extend in the X-direction, whereas the comb toothportions 131 b extend in a direction opposite to the X-direction.Similarly to the comb tooth portions 131 a or the comb tooth portions131 b, the electrode base portion 132 is made of translucent conductivematerial (translucent conductive oxide) such as indium tin oxide (ITO).

The first orientation film 73 a described above is subjected toorientation processing in an orientation direction ORI (a firstorientation direction) illustrated in FIGS. 3 and 5 such that the liquidcrystal molecules have a certain initial orientation in the X-direction.The second orientation film 73 b is subjected to orientation processingin a direction (a second orientation direction) antiparallel to theorientation direction ORI of the first orientation film 73 a. Theorientation directions of the first orientation film 73 a and the secondorientation film 73 b are antiparallel to each other. As describedabove, the comb tooth portions 131 a extend in the X-direction, and thecomb tooth portions 131 b extend in the direction opposite to theX-direction. The orientation direction ORI is parallel to the directionin which the comb tooth portions 131 a or the comb tooth portions 131 bextend. The orientation direction ORI is considered to be parallel aslong as it is sufficiently parallel to maintain the rotation directionof liquid crystal molecules LCM illustrated in FIG. 9, which will bedescribed later. More specifically, the orientation direction ORI allowsa manufacturing error of 0 degree or greater to 0.5 degree or less. Toprovide a certain orientation to the liquid crystal molecules, thefollowing orientation films may be used: an orientation film formed byperforming rubbing on an organic film such as a polyimide; or an opticalorientation film that can be provided with a specific liquid-crystalorientation capability by irradiating the film with light such asultraviolet rays. In this way, according to the embodiment, the firstorientation film 73 a and the second orientation film 73 b are subjectedto rubbing treatment to have the certain initial orientation. However, amethod of providing an initial orientation to the first orientation film73 a and the second orientation film 73 b is not limited to the rubbingtreatment. The first orientation film 73 a and the second orientationfilm 73 b may be formed by using a material having optical orientationto have the certain initial orientation.

FIG. 6 is a schematic diagram for explaining a relation between theshape of the first electrode and a shaded position according to theembodiment. The black matrix 76 a only needs to shade the sub-pixel Vpixto the position of a width 76 h 1 a illustrated in FIG. 6, therebyhiding the contact 90H. An electric field applied to the endmost slit Swbetween the comb tooth portion 131 b closest to the edge of the aperture76 b and the contact 90H has different distribution from that of anelectric field applied to the slit S between adjacent comb toothportions 131 a or between adjacent comb tooth portions 131 b. If theblack matrix 76 a shades the sub-pixel Vpix to the position of a width76 h 1 b illustrated in FIG. 6 to hide the contact 90H and more thanhalf of the endmost slit Sw, the rate of change in the transmittance ofthe endmost slit Sw can be made closer to that of the slit S.Alternatively, if the black matrix 76 a shades the sub-pixel Vpix to theposition of a width 76 h 1 c illustrated in FIG. 6 to hide the contact90H and the endmost slit Sw, it is not necessary to consider thedifference between the rates of change in the transmittance of theendmost slit Sw and the slit S. This structure can make luminance in theaperture 76 b uniform.

FIG. 7 is an explanatory diagram for explaining orientation of theliquid crystals in a state where no voltage to generate an electricfield between the first electrode and the second electrode is applied inthe liquid crystal display device according to the embodiment. FIG. 8 isa schematic diagram illustrating a sectional view along the line B1-B2of FIG. 7. FIG. 9 is an explanatory diagram for explaining orientationof the liquid crystals in a state where the voltage to generate anelectric field between the first electrode and the second electrode isapplied in the liquid crystal display device according to theembodiment. FIG. 10 is a schematic diagram illustrating a sectional viewalong the line C1-C2 of FIG. 9. FIG. 11 is a schematic diagram forexplaining in detail the shape of the first electrode in the pixelaccording to the embodiment.

As described above, the first orientation film 73 a is subjected toorientation processing in the orientation direction ORI illustrated inFIGS. 3 and 5 such that the liquid crystal molecules have a certaininitial orientation in the X-direction. In a case where no voltage togenerate an electric field between the first electrode 31 and the secondelectrode 32 is applied, the long-axis direction of liquid crystalmolecules Lcm in the liquid crystal layer 70C tends to be alignedparallel to the direction in which the comb tooth portions 131 a and thecomb tooth portions 131 b extend as illustrated in FIG. 7. As a result,the liquid crystal molecules Lcm are initially oriented parallel to thedirection in which the comb tooth portions 131 a and the comb toothportions 131 b extend at neighboring areas of a right long side 131R anda left long side 131L of the comb tooth portions 131 a and the combtooth portions 131 b facing each other in the width direction of theslit S. The liquid crystal molecules Lcm illustrated in FIG. 8 areinitially oriented along the orientation direction ORI and upward withrespect to the orientation direction ORI so as to have a pretilt angleθp with respect to the surface of the TFT substrate 71.

When a voltage to generate an electric field between the first electrode31 and the second electrode 32 is applied, the liquid crystal moleculesLcm rotate in a liquid-crystal rotation direction LCQ as illustrated inFIG. 9. In other words, the liquid-crystal rotation direction LCQ is adirection of twist or rotation of the liquid crystals in the X-Y plane.The liquid crystal molecules Lcm positioned at the neighboring area ofthe right long side 131R and those at the neighboring area of the leftlong side 131L are affected by electric fields in opposite directionsand thus are likely to rotate in opposite directions.

As described above, when a voltage is applied to the first electrode 31and the second electrode 32, in the liquid crystal layer 70C of theliquid crystal display device 1 according to the embodiment, the liquidcrystal molecules Lcm in the neighboring area of the right long side131R rotate in a direction opposite to a rotating direction of those inthe neighboring area of the left long side 131L. The right long side131R is one of the sides of adjacent comb tooth portions 131 a (131 b)facing the slit S in the width direction thereof, whereas the left longside 131L is the other of the sides. The liquid crystal molecules Lcmrespond to a change in the electric field between the first electrode 31and the second electrode 32 at higher speed in the liquid crystaldisplay device 1 according to the embodiment than in the FFS-mode liquidcrystal display device disclosed in JP-A-2008-52161. As a result, theliquid crystal display device 1 according to the embodiment achieves ahigher response speed.

The response speed is a speed at which the transmittance of the liquidcrystals is shifted between certain levels when a voltage is applied tothe first electrode 31 and the second electrode 32. In other words, theresponse speed is specified by a time required to shift thetransmittance from a state where no voltage is applied (for example,transmittance=0) to a state where a voltage is applied (transmittance=1)or a time required to shift the transmittance from the state where avoltage is applied to the state where no voltage is applied.

When a voltage to generate an electric field between the first electrode31 and the second electrode 32 is applied, the long-axis direction ofthe liquid crystal molecules Lcm rotates in a plane (X-Y plane) parallelto the surface of the pixel substrate 70A (TFT substrate 71) and changesalso in the Z-direction as illustrated in FIG. 10. The first electrode31 and the second electrode 32 are arranged facing each other in adirection perpendicular to the surface of the pixel substrate 70A (TFTsubstrate 71). Therefore, the electric field generated between the firstelectrode 31 and the second electrode 32 serves as a fringe electricfield passing through the slits S. The fringe electric field causes thelong axis of the liquid crystal molecules Lcm to rotate in theliquid-crystal rotation directions LCQ (clockwise and counterclockwise)in the X-Y plane illustrated in FIG. 9 and to rise in the direction(Z-direction) perpendicular to the surface of the pixel substrate 70A(TFT substrate 71). The liquid-crystal rotation directions LCQ maypossibly be mixed at the center area of the slits S.

As illustrated in FIG. 10, the long-axis direction of the liquid crystalmolecules Lcm has an angle θp2 larger than the pretilt angle θp in aslit area Rs between the comb tooth portions 131 b. The long-axisdirection of the liquid crystal molecules Lcm has an angle θpl oppositeto the pretilt angle θp in a slit area Ls between the comb toothportions 131 a. The long-axis direction of the liquid crystal moleculesLcm in the slit area Ls is less likely to rise and may have lowerorientation stability than the long-axis direction of the liquid crystalmolecules Lcm in the slit area Rs does.

By specifying the shape of the first electrode 31 more finely asillustrated in FIG. 11, it is possible to increase the responsiveness ofthe liquid crystal display device 1 according to the embodiment. Asillustrated in FIG. 11, L0 represents a total slit length between theelectrode base portions 132 in the X-direction, for example. L1represents a comb tooth protrusion length of the comb tooth portions 131a in the X-direction. The comb tooth protrusion length L1 corresponds toa length from a position x1 of a tip 131 af of the comb tooth portions131 a to a protrusion start position x0 in the electrode base portion132. Similarly, L2 represents a comb tooth protrusion length of the combtooth portions 131 b in the X-direction. The comb tooth protrusionlength L2 corresponds to a length from a position x1 of a tip 131 bf ofthe comb tooth portions 131 b to a protrusion start position x0 in theelectrode base portion 132. The width of the tip 131 af of the combtooth portions 131 a and the tip 131 bf of the comb tooth portions 131 bin the Y-direction is w1. The total slit length L0 is preferably set toa value equal to or greater than 10 μm to a value equal to or smallerthan 60 μm, for example. The total slit length L0 is more preferably setsmaller than 40 μm, specifically to 20 μm, for example. In the liquidcrystal display device 1 according to the embodiment, a decrease in thetotal slit length L0 increases the orientation stability of the liquidcrystals, whereas an increase in the total slit length L0 increases theluminance.

As described above, the liquid crystal molecules Lcm in the slit area Lsin FIG. 10 may possibly be less likely to rise in the long-axisdirection than those in the slit area Rs in the long-axis direction andhave lower orientation stability than those in the slit area Rs do. Tomake the slit area Ls smaller than the slit area Rs, the comb toothprotrusion length L1 illustrated in FIG. 11 is made smaller than thecomb tooth protrusion length L2 of the comb tooth portions 131 bpositioned on the upstream of the comb tooth portions 131 a in theorientation direction ORI. Thus, the liquid crystal display device 1according to the embodiment can increase the orientation stability.

The width w1 of the tip 131 af of the comb tooth portions 131 a and thetip 131 bf of the comb tooth portions 131 b in the Y-direction is set toa value equal to or greater than 2 μm to a value equal to or smallerthan 5 μm, for example. Setting the width w1 to a smaller value canincrease the response speed.

A slit pitch (an array pitch) p between adjacent comb tooth portions 131a is equal to an array pitch between adjacent comb tooth portions 131 b.The tip 131 af of the comb tooth portions 131 a and the tip 131 bf ofthe comb tooth portions 131 b are arranged alternately in theY-direction. With this structure, the right long side 131R of the combtooth portions 131 a and the right long side 131R of the comb toothportions 131 b are aligned in the X-direction as illustrated in FIG. 9.With this structure, the left long side 131L of the comb tooth portions131 a and the left long side 131L of the comb tooth portions 131 b arealso aligned in the X-direction as illustrated in FIG. 9. As a result,the liquid-crystal rotation directions LCQ in which the liquid crystalmolecules Lcm rotate are the same direction viewed in the X-direction,thereby stabilizing the rotation behavior of the liquid crystalmolecules Lcm. Because a decrease in the slit pitch p increases theresponse speed, the slit pitch p is preferably set smaller than 9 μm.

The gap between the tip 131 af of the comb tooth portions 131 a and thetip 131 bf of the comb tooth portions 131 b illustrated in FIG. 11corresponds to a width W in the X-direction of a communicating apertureextending in the Y-direction. The width W is preferably set to a smallervalue. The width W of the communicating aperture in the X-direction isset to 7 μm or smaller, for example, and more preferably to 4 μm orsmaller. The width W of the communicating aperture in the X-directionmay be set to 0 or smaller. In a case where W=0 is satisfied, forexample, the tip 131 af of the comb tooth portions 131 a and the tip 131bf of the comb tooth portions 131 b are aligned in the Y-direction. Inthis case, the tips are arranged with gaps interposed therebetween inthe Y-direction, whereby a plurality of slits S communicate with oneanother. In a case where W<0 is satisfied, the tip 131 af of the combtooth portions 131 a and the tip 131 bf of the comb tooth portions 131 benter into respective slits S adjacent thereto in the X-direction. Inother words, the comb tooth portions 131 a and the comb tooth portion131 b are alternately engaged.

The width of the comb tooth portions 131 a in the Y-direction at theprotrusion start position x0 in the electrode base portion 132 isrepresented by w2 and is larger than the width w1 of the tip 131 af ofthe comb tooth portions 131 a in the Y-direction. Thus, the comb toothportions 131 a have a trapezoidal shape. A long side 131 a 11 and a longside 131 a 12 of the comb tooth portions 131 a are oblique to areference direction of a virtual line 131 ac passing through the centerof the comb tooth portions 131 a (X-direction in which the comb toothportions 131 a extend) by an angle θ. Setting the angle θ larger than0.5 degree can facilitate alignment of the liquid-crystal rotationdirections LCQ in which the liquid crystal molecules Lcm rotate, therebystabilizing the behavior of the liquid crystal molecules Lcm. The shapeof the comb tooth portions 131 a has been exemplified as a trapezoidalshape such that the left and the right sides at least partially haveobliquity opposite to each other with respect to the extendingdirection. The shape of the comb tooth portions 131 a is not limitedthereto. The obliquity of the left and the right sides of the comb toothportions 131 a with respect to the extending direction may be differentbetween a base area closer to the base portion and a tip area away fromthe base portion.

Similarly, the width of the comb tooth portions 131 b in the Y-directionat the protrusion start position x0 in the electrode base portion 132 isrepresented by w2 and is larger than the width w1 of the tip 131 bf ofthe comb tooth portions 131 b in the Y-direction. Thus, the comb toothportions 131 b have a trapezoidal shape. A long side 131 b 11 and a longside 131 b 12 of the comb tooth portions 131 b are oblique to areference direction of a virtual line 131 bc passing through the centerof the comb tooth portions 131 b (X-direction in which the comb toothportions 131 b extend) by an angle θ. Setting the angle θ larger than0.5 degree can facilitate alignment of the liquid-crystal rotationdirections LCQ in which the liquid crystal molecules Lcm rotate, therebystabilizing the behavior of the liquid crystal molecules Lcm. Becausethe liquid-crystal rotation directions LCQ are aligned in lines adjacentto each other in the X-direction and on the X-direction line in theliquid crystal display device 1 according to the embodiment, highorientation stability can be achieved. The shape of the comb toothportions 131 b has been exemplified as a trapezoidal shape such that theleft and the right sides at least partially have obliquity opposite toeach other with respect to the extending direction. The shape of thecomb tooth portions 131 b is not limited thereto. The obliquity of theleft and the right sides of the comb tooth portions 131 b with respectto the extending direction may be different between a base area closerto the base portion and a tip area away from the base portion.

When the comb tooth protrusion length L1 of the comb tooth portions 131a or the comb tooth protrusion length L2 of the comb tooth portions 131b is increased, it is necessary to increase the angle θ. An increase inthe angle increases the difference between the width w1 and the widthw2, resulting in limitation on the slit pitch p. In a case where theangle θ is 0.5 degree or greater to 1.0 degree or less, for example, thecomb tooth protrusion length L1 of the comb tooth portions 131 a or thecomb tooth protrusion length L2 of the comb tooth portions 131 b ispreferably set to 45 μm or smaller.

Because the electrode base portion 132 does not contribute totransmission of light, a width D1 of the electrode base portion 132 inthe X-direction (a direction orthogonal to the extending direction ofthe electrode base portion 132) is preferably set to a smaller value.The width D1 is preferably set larger than 0 μm and equal to or smallerthan 4 μm. Setting the width D1 larger than 0 μm can increase theconductivity, whereas setting the width D1 equal to or smaller than 4 μmcan suppress decrease in the transmittance. In a case where the width D1is larger than 0 μm and equal to or smaller than 4 μm and where the combtooth protrusion length L1 of the comb tooth portions 131 a or the combtooth protrusion length L2 of the comb tooth portions 131 b is 45 μm orsmaller, the display area 21 can serve as a high-definition screen of160 pixels per inch (ppi) or higher. In a case where the width w1 is 0.5for example, the width w2 is preferably set to 1 μm or larger to ensurethe quality throughout the comb tooth protrusion length L1 of the combtooth portions 131 a or the comb tooth protrusion length L2 of the combtooth portions 131 b.

As described above, setting the slit pitch p to a smaller value canincrease the response speed. A decrease in the slit pitch p, however,increases the width of the comb tooth portions 131 a or the comb toothportions 131 b in the Y-direction, for example, resulting in an increasein the area that does not contribute to transmission of light. Thetransmittance can be effectively increased by an increase in the combtooth protrusion length L1 of the comb tooth portions 131 a or the combtooth protrusion length L2 of the comb tooth portions 131 b. However,the increase in the length can possibly make alignment of theliquid-crystal rotation directions LCQ, in which the liquid crystalmolecules Lcm rotate, difficult, resulting in instability in thebehavior of the liquid crystal molecules Lcm.

FIG. 12 is a schematic diagram for explaining in detail a transmissionineffective area according to the embodiment. FIG. 13 is a schematicdiagram illustrating a disclination line of the first electrodeaccording to the embodiment. In the embodiment, a boundary betweenclockwise rotation and counterclockwise rotation of the liquid crystalsis referred to as disclination. Due to this structure, first comb toothportions 131 a and second comb tooth portions 131 b are opposed to eachother with a transmission ineffective area np interposed therebetween.The transmission ineffective area np is an area which includes notranslucent conductive material. Even when a voltage is applied to thefirst electrode 31, the liquid crystal molecules Lcm hardly move in thetransmission ineffective area np. As a result, the transmittance isreduced in the transmission ineffective area np. The liquid crystalshardly move also in a region overlapping with the electrode base portion132. Therefore, each of the comb tooth protrusion lengths L1 and L2illustrated in FIG. 11 is a transmission effective interval Em in theX-direction in which the liquid crystal molecules Lcm effectively rotateeven if a voltage is applied to the first electrode 31.

As illustrated in FIG. 13, a disclination line dc1 in which the liquidcrystal molecules hardly move even if a voltage is applied to the firstelectrode 31 is likely to be generated at the center of the first combtooth portion 131 a, the center of the second comb tooth portion 131 b,the center between adjacent first comb tooth portions 131 a, and thecenter between adjacent second comb tooth portions 131 b. As illustratedin FIGS. 12 and 13, the first electrode 31 is configured such that thetip 131 af of the first comb tooth portion 131 a and the tip 131 bf ofthe second comb tooth portion 131 b are alternately arranged in theY-direction. Due to this, orientations AXI of the liquid crystalmolecules Lcm are the same in a line LQ1. The orientations AXI of theliquid crystal molecules Lcm are the same also in a line LQ2. As aresult, the disclination line dc1 generated at the center of the firstcomb tooth portion 131 a and the disclination line dc1 generated at thecenter between the adjacent second comb tooth portions 131 b areconnected to make the disclination line dc1 easier to be seen. Thedisclination line dc1 generated at the center of the second comb toothportion 131 b and the disclination line dc1 generated at the centerbetween the adjacent first comb tooth portions 131 a are connected tomake the disclination line dc1 easier to be seen. As described above,the first electrode 31 illustrated in FIG. 13 includes many disclinationlines dc1, and a period of change in transmittance in the Y-direction isshortened.

FIG. 14 is a schematic diagram for explaining in detail the transmissionineffective area according to a first modification of the embodiment.FIG. 15 is a schematic diagram illustrating the disclination line of thefirst electrode according to the first modification of the embodiment.As illustrated in FIGS. 14 and 15, in the first electrode 31 accordingto the first modification of the embodiment, a plurality of first combtooth portions 131 a 1 and first comb tooth portions 131 as alternatelyprotrude from the electrode base portion 132 at a certain distance fromeach other. A plurality of second comb tooth portions 131 b 1 and secondcomb tooth portions 131 bs alternately protrude from the electrode baseportion 132 at a certain distance from each other.

As illustrated in FIG. 15, in the area in which the first comb toothportions 131 a 1 are adjacent to the first comb tooth portions 131 as inthe width direction of the slit S, the liquid crystal molecules Lcm inthe neighboring areas of respective adjacent long sides are oblique tothe X-direction in opposite directions. In the area in which the firstcomb tooth portions 131 a 1 are adjacent to the second comb toothportions 131 b 1 in the width direction of the slit S, the liquidcrystal molecules Lcm in the neighboring areas of respective adjacentlong sides are oblique to the X-direction in the same direction. In thearea in which the second comb tooth portions 131 b 1 are adjacent to thesecond comb tooth portions 131 bs in the width direction of the slit S,the liquid crystal molecules Lcm in the neighboring areas of respectiveadjacent long sides are oblique to the X-direction in oppositedirections. Due to this, when the neighboring areas of two right longsides arranged in a line in the X-direction and the neighboring areas oftwo left long sides arranged in a line in the X-direction are viewedfrom one of the adjacent electrode base portions 132 toward the otherone thereof, the liquid crystal molecules are arranged in oppositedirections, the same direction, and opposite directions, in order. Theliquid crystal molecules Lcm in the respective neighboring areas of theleft long side of the first comb tooth portion 131 a 1 and the left longside of the second comb tooth portion 131 b 1 which are arranged in aline in the X-direction are oblique to the X-direction in oppositedirections. The liquid crystal molecules Lcm in the respectiveneighboring areas of the right long side of the first comb tooth portion131 a 1 and the right long side of the second comb tooth portion 131 b 1which are arranged in a line in the X-direction are oblique to theX-direction in opposite directions. The liquid crystal molecules Lcm inthe respective neighboring areas of the left long side of the first combtooth portion 131 as and the left long side of the second comb toothportion 131 bs which are arranged in a line in the X-direction areoblique to the X-direction in opposite directions. The liquid crystalmolecules Lcm in the respective neighboring areas of the right long sideof the first comb tooth portion 131 as and the right long side of thesecond comb tooth portion 131 bs which are arranged in a line in theX-direction are oblique to the X-direction in opposite directions.Accordingly, the disclination line dc1 generated at the center of thesecond comb tooth portion 131 b and the disclination line dc1 generatedat the center between the adjacent first comb tooth portions 131 a areseparated from each other. In this way, in the first electrode 31illustrated in FIG. 15, a decrease in transmittance of the disclinationline dc1 is suppressed, and a period of change in the transmittance inthe Y-direction is lengthened. The liquid crystal display device 1according to the first modification of the embodiment can thus improvethe transmittance in addition to providing excellent properties such asa fast response and a wide viewing angle.

FIG. 16 is an explanatory diagram illustrating light transmittancedistribution due to the disclination line of the first electrodeaccording to a comparative example. FIG. 17 is an explanatory diagramillustrating a positional relation between the light transmittancedistribution due to the disclination line of the first electrodeaccording to the embodiment and the light-blocking part. FIGS. 16 and 17both represent the area in which the liquid crystal molecules move whena voltage is applied to the first electrode 31 as a white area, andrepresents the disclination line dc1 and the transmission ineffectivearea np as a black area. The disclination line dc1 and the transmissionineffective area np have a contrast different from that of the area inwhich light is blocked with the black matrix 76 a. For example, thewhite area illustrated in FIG. 16 has a contrast of 0.1:200 (black:white). The black area including the disclination line dc1 and thetransmission ineffective area np has a contrast of 0.1:0.1(black:white). On the other hand, the area in which light is blockedwith the black matrix 76 a has a contrast of 0.001:0.001 (black:white).As a result, the contrast of the whole sub-pixels is about 1:1300(black:white).

The liquid crystal display device 1 according to the embodimentincludes, as illustrated in FIG. 4, at least one of the light-blockingpart 76 c and the light-blocking part 76 d. As illustrated in FIG. 17,when the black area of the disclination line dc1 is overlapped with atleast one of the light-blocking part 76 c and the light-blocking part 76d, the black area of the light-blocking area generated by at least oneof the light-blocking part 76 c and the light-blocking part 76 d shows acontrast close to the contrast of the area in which light is blockedwith the black matrix 76 a. The black area of the light-blocking areagenerated by the light-blocking part 76 c and the light-blocking part 76d has a contrast of 0.001:0.001 (black:white). As a result, the contrastof the whole sub-pixels can be made close to about 1:2000 (black:white).For example, the width of the black area of the disclination line dc1 isabout half or below the width of the comb tooth portion, or about halfor below the width of the slit S. In addition to the light-blocking part76 c or the light-blocking part 76 d illustrated in FIG. 17, anotherlight-blocking part may overlap with the transmission ineffective areanp. Another light-blocking part can intersect with the light-blockingpart 76 c or the light-blocking part 76 d to make the black area of thelight-blocking area have a grid shape.

The liquid crystal display device 1 according to the embodiment includesat least one of the light-blocking part 76 c and the light-blocking part76 d illustrated in FIG. 4 for reducing intensity of light passingtherethrough at a position overlapping with the center of the first combtooth portion 131 a and the center between the adjacent first comb toothportions 131 a in a direction perpendicular to the first substrate. Theliquid crystal display device 1 according to the embodiment alsoincludes at least one of the light-blocking part 76 c and thelight-blocking part 76 d illustrated in FIG. 4 for reducing intensity oflight passing therethrough at a position overlapping with the center ofthe second comb tooth portion 131 b and the center between the adjacentsecond comb tooth portions 131 b in a direction perpendicular to thefirst substrate. Accordingly, as illustrated in FIG. 17, at least one ofthe light-blocking part 76 c and the light-blocking part 76 d canoverlap with the black area of the disclination line dc1. As a result,the contrast of the whole sub-pixels can be improved. As illustrated inFIG. 17, the light-blocking part 76 c and the light-blocking part 76 dare arranged both at the center of the first comb tooth portion 131 aand at the center between the adjacent first comb tooth portions 131 a.The arrangement of the light-blocking part 76 c and the light-blockingpart 76 d is not limited thereto. The light-blocking part may bearranged at least at any of the center of the first comb tooth portion131 a and the center between the adjacent first comb tooth portions 131a. As exemplified in the arrangement of the light-blocking part 76 c andthe light-blocking part 76 d, the light-blocking part may be formed onboth of the TFT substrate 71 serving as the first substrate and theglass substrate 72 serving as the second substrate, or formed on any oneof the first substrate and the second substrate.

As in the liquid crystal display device 1 according to the firstmodification of the embodiment, when the respective tips 131 af and 131bf of the first comb tooth portion 131 a and the second comb toothportion 131 b extending from the adjacent electrode base portions 132are opposed to each other at a distance, at least one of thelight-blocking part 76 c and the light-blocking part 76 d illustrated inFIG. 4 for reducing intensity of light passing therethrough may beprovided at a position overlapping with the center of the first combtooth portion 131 a in a direction perpendicular to the first substrate.Accordingly, as illustrated in FIG. 17, at least one of thelight-blocking part 76 c and the light-blocking part 76 d can overlapwith the black area of the disclination line dc1. The number ofdisclination lines dc1 of the first electrode 31 according to the firstmodification of the embodiment is smaller than that of disclinationlines dc1 illustrated in FIG. 13, so that transmittance can be furtherimproved.

As illustrated in FIGS. 13 and 15, the present inventors have foundthat, in a case where an interval between the disclination lines dc1 is1, a decrease in the interval 1 increases the response speed. Theinterval 1 is not necessarily a fixed interval as long as an averagevalue of intervals 1 is equal to or smaller than a certain value(hereinafter, referred to as an average interval 1). The averageinterval 1 may be equal to or smaller than 10 μm, for example.

Similarly, the present inventors have found that a decrease in thetransmission effective interval Em also increases the response speed.The transmission effective interval Em is not necessarily a fixedinterval as long as an average value of transmission effective intervalsEm is equal to or smaller than a certain value (hereinafter, referred toas an average transmission effective interval Em). The averagetransmission effective interval Em may be equal to or smaller than 10μm, for example.

In this way, the liquid crystal display device 1 according to theembodiment and the first modification improves the contrast of thesub-pixels Vpix while improving the response speed of the entire pixelsPix to further improve display quality in the plane.

Manufacturing Method

The method for manufacturing the liquid crystal display device 1according to the embodiment includes the following process, for example.A manufacturing apparatus performs a first substrate preparation processto prepare a glass substrate, which is a translucent substrate, as theTFT substrate 71 of the pixel substrate (first substrate) 70A.

Subsequently, the manufacturing apparatus forms the scanning line 24_(m) and the gate electrode 93 on the TFT substrate 71. Themanufacturing apparatus then forms an insulation film 741 between thescanning line 24 _(m) and the gate electrode 93, and the semiconductorlayer 92 to be formed, on the TFT substrate 71. The manufacturingapparatus then forms the layer of the source electrode 91, the drainelectrode 90, and the semiconductor layer 92, for example. Themanufacturing apparatus then forms an insulation film 742 between thesemiconductor layer 92 and the signal line 25 _(n) to be formed. Themanufacturing apparatus then forms the signal line 25 _(n) and couplesthe signal line 25 _(n) to the source electrode 91. The manufacturingapparatus then forms an insulation film 743 between the signal line 25_(n) and the second electrode 32 to be formed.

Subsequently, the manufacturing apparatus forms the second electrode 32serving as a pixel electrode by sputtering or etching, for example. Themanufacturing apparatus then couples the drain electrode 90 and thesecond electrode 32 via the conductive contact 90H. The thickness of thesecond electrode 32 is 10 nm or greater to 100 nm or less, for example.The manufacturing apparatus then forms the insulation film 744 on thesecond electrode 32 by plasma-enhanced chemical vapor deposition (CVD),for example.

Subsequently, the manufacturing apparatus forms the first electrode 31by sputtering or etching, for example. The manufacturing apparatus thencouples the first electrode 31 to the driver IC 3 such that the firstelectrode 31 functions as the common electrode COM. The thickness of thefirst electrode 31 is 10 nm or greater to 100 nm or less, for example.The first electrode 31 is formed into a comb teeth shape with the slitsS. The manufacturing apparatus then forms the first orientation film 73a, which is obtained by performing processing in the orientationdirection ORI on a polymeric material such as a polyimide, on the firstelectrode 31. Thus, the manufacturing apparatus performs themanufacturing process of the first substrate.

The manufacturing apparatus performs a second substrate preparationprocess to prepare a glass substrate, which is a translucent substrate,as the glass substrate 72 of the counter substrate (second substrate)70B.

The manufacturing apparatus forms the layer of the color filters 76R,76G, and 76B and the black matrix 76 a on the glass substrate 72 andthen forms an overcoat layer and the like on the layer. Themanufacturing apparatus then forms the second orientation film 73 b,which is obtained by performing processing antiparallel (in an oppositedirection) to the orientation direction ORI on a polymeric material suchas a polyimide, on the overcoat layer. Thus, the manufacturing apparatusperforms the manufacturing process of the second substrate. The colorfilters 76R, 76G, and 76B, and the black matrix 76 a may be arranged onthe TFT substrate 71 instead of the glass substrate 72. That is, thelight-blocking part having a light blocking property that covers eachaperture of the color filters 76R, 76G, and 76B may be formed at leaston any of the glass substrate 72 (second substrate) and the TFTsubstrate 71 (first substrate). The light-blocking part arranged at thecenter of the comb tooth portion or the center between the comb toothportions may also be formed in the same layer as the light-blocking partcovering each aperture of the color filters 76R, 76G, and 76B formed onany of the glass substrate 72 (second substrate) and the TFT substrate71 (first substrate).

The manufacturing apparatus causes the pixel substrate 70A and thecounter substrate 70B to face each other. The manufacturing apparatusinjects liquid crystals between the substrates and seals the liquidcrystal section with a frame edge, thereby forming the liquid crystallayer 70C. The back surface of the pixel substrate 70A is provided witha polarizing plate and the backlight 6, whereas the front surfacethereof is provided with a polarizing plate and the like. The driver IC3 is coupled to an electrode terminal on the frame edge. Thus, theliquid crystal display device 1 is manufactured.

While the embodiment uses amorphous silicon (a-Si) as the semiconductorlayer 92 forming the TFT element Tr, it is not limited thereto. Theembodiment may use polycrystalline silicon (poly-Si) as thesemiconductor layer 92. The embodiment may use another semiconductormaterial (for example, germanium (Ge)) instead of silicon or a materialobtained by adding another material to silicon (for example, silicongermanium (SiGe)). The embodiment may use an oxide semiconductormaterial as the semiconductor layer 92. Examples of the oxidesemiconductor material include, but are not limited to, an oxidesemiconductor material including indium (In), etc.

In the embodiment, the TFT element Tr is a bottom gate TFT in which thegate electrode 93 is provided below the semiconductor layer 92. Theembodiment may use a top gate TFT in which the gate electrode 93 isprovided above the semiconductor layer 92 if possible. In the case ofusing a top gate TFT as the TFT element Tr, the manufacturing apparatusmanufactures: the semiconductor layer 92, the scanning line 24 _(m) andthe gate electrode 93, and the signal line 25 _(n) in this order; or thesemiconductor layer 92, the signal line 25 _(n), and the scanning line24 _(m) and the gate electrode 93 in this order, instead of themanufacturing process described above.

The liquid crystal display device 1 according to a second modificationof the embodiment will be described. FIG. 18 is a schematic diagramillustrating a modification of the sectional view along the line A1-A2of FIG. 3 as the liquid crystal display device according to the secondmodification of the embodiment. Components identical to those describedin the embodiment are denoted by like reference numerals, andoverlapping explanation thereof will not be repeated.

The liquid crystal display device 1 according to the second modificationof the embodiment generates an electric field (a horizontal electricfield) between the first electrode 31 and the second electrode 32laminated in a direction (Z-direction) perpendicular to the surface ofthe TFT substrate 71 of the pixel substrate 70A and in a directionparallel to the TFT substrate 71. As a result, liquid crystal moleculesin the liquid crystal layer 70C rotate in a plane parallel to thesubstrate surface. The liquid crystal display device 1 uses a change inthe light transmittance corresponding to the rotation of the liquidcrystal molecules, thereby performing display. The second electrode 32illustrated in FIG. 18 is the common electrode COM, whereas the firstelectrode 31 is the pixel electrode, for example. The first electrode 31is coupled to the drain electrode 90 via the conductive contact 90H, forexample. The first electrode 31 is sectioned by each area of thesub-pixel Vpix and has an independent pattern electrically insulatedfrom the first electrode 31 in an area of the sub-pixel Vpix adjacentthereto. The liquid crystal display device 1 according to the embodimentexhibits the same advantage in both of the embodiment and the secondmodification.

The liquid crystal display device 1 according to a third modification ofthe embodiment will be described. FIG. 19 is a schematic diagram forexplaining the modification of a relation between the shape of the firstelectrode and the aperture as the liquid crystal display deviceaccording to the third modification of the embodiment. Componentsidentical to those described in the embodiment are denoted by likereference numerals, and overlapping explanation thereof will not berepeated.

The first electrode 31 includes the comb tooth portions 131 protrudingfrom the electrode base portion 132 extending in the X-direction. Thecomb tooth portions 131 include the comb tooth portions 131 a and thecomb tooth portions 131 b extending in opposite directions from theelectrode base portion 132. Adjacent comb tooth portions 131 a protrudefrom the electrode base portion 132 with a certain distance interposedtherebetween. Similarly, adjacent comb tooth portions 131 b protrudefrom the electrode base portion 132 with a certain distance interposedtherebetween. From each electrode base portion 132, the comb toothportions 131 a extend in the Y-direction, whereas the comb toothportions 131 b extend in a direction opposite to the extending directionof the comb tooth portions 131 a in the Y-direction.

The first orientation film 73 a is subjected to orientation processingin the orientation direction ORI illustrated in FIG. 19 such that theliquid crystal molecules have a certain initial orientation in theY-direction. The second orientation film 73 b is subjected toorientation processing antiparallel to the orientation direction ORI ofthe first orientation film 73 a. The orientation directions ORI of thefirst orientation film 73 a and the second orientation film 73 b areantiparallel to each other. As described above, the comb tooth portions131 a extend in the Y-direction, and the comb tooth portions 131 bextend in the direction opposite to the Y-direction. The orientationdirection ORI is parallel to the direction in which the comb toothportions 131 a and the comb tooth portions 131 b extend. The orientationdirection ORI is considered to be parallel as long as it is sufficientlyparallel to maintain the rotation direction of liquid crystal moleculesLCM illustrated in FIG. 9. More specifically, the orientation directionORI allows a manufacturing error of 0 degree or greater to 0.5 degree orless. The liquid crystal display device 1 according to the embodimentexhibits the same advantage in both of the embodiment and the thirdmodification.

The liquid crystal display device 1 according to a fourth modificationof the embodiment will be described. FIG. 20 is a plan view forexplaining the pixel as the liquid crystal display device according tothe fourth modification of the embodiment. FIG. 21 is a schematicdiagram illustrating a sectional view along the line E1-E2 of FIG. 20.Components identical to those described in the embodiment are denoted bylike reference numerals, and overlapping explanation thereof will not berepeated.

As illustrated in FIG. 20, the semiconductor layer 92 is polycrystallinesilicon (poly-Si) forming the TFT element Tr. The semiconductor layer 92is a double-gate transistor forming a channel with two areas.

As illustrated in FIGS. 20 and 21, the liquid crystal display device 1according to the fourth modification of the embodiment generates anelectric field (a horizontal electric field) between the first electrode31 and the second electrode 32 laminated in a direction (Z-direction)perpendicular to the surface of the TFT substrate 71 of the pixelsubstrate 70A in a direction parallel to the TFT substrate 71. As aresult, liquid crystal molecules in the liquid crystal layer 70C rotatein a plane parallel to the substrate surface. The liquid crystal displaydevice 1 uses a change in the light transmittance corresponding to therotation of the liquid crystal molecules, thereby performing display.The second electrode 32 illustrated in FIG. 21 is the common electrodeCOM, whereas the first electrode 31 is the pixel electrode, for example.The first electrode 31 is coupled to the conductive drain electrode 90,for example. The first electrode 31 is sectioned by each area of thesub-pixel Vpix and has an independent pattern electrically insulatedfrom the first electrode 31 in an area of the sub-pixel Vpix adjacentthereto.

The first orientation film 73 a is subjected to orientation processingin the orientation direction ORI such that the liquid crystal moleculeshave a certain initial orientation in the X-direction. The secondorientation film 73 b is subjected to orientation processingantiparallel to the orientation direction ORI of the first orientationfilm 73 a. The orientation directions of the first orientation film 73 aand the second orientation film 73 b are antiparallel to each other.

Similarly to the liquid crystal display device 1 according to theembodiment, in the liquid crystal layer 70C of the liquid crystaldisplay device 1 according to the fourth modification of the embodiment,applying a voltage to the first electrode 31 and the second electrode 32rotates the liquid crystal molecules in the neighboring area of theright long side 131R and those in the neighboring area of the left longside 131L in opposite directions. The right long side 131R is one of thesides of adjacent comb tooth portions 131 c facing each other in thewidth direction of the slit S, whereas the left long side 131L is theother of the sides. Thus, the liquid crystal molecules respond to achange in the electric field between the first electrode 31 and thesecond electrode 32 at higher speed in the liquid crystal display device1 according to the fourth modification of the embodiment than in theFFS-mode liquid crystal display device disclosed in JP-A-2008-52161. Asa result, the liquid crystal display device 1 according to the fourthmodification of the embodiment achieves a higher response speed.

Similarly to the comb tooth protrusion length L2 of the comb toothportions 131 b, in a case where a comb tooth protrusion length of thecomb tooth portions 131 c increases, it is necessary to increase theangle θ. An increase in the angle increases the difference between thewidth w1 and the width w2, resulting in limitation on the slit pitch p.In a case where the angle θ is 0.5 degree or greater to 1.0 degree orless, for example, the comb tooth protrusion length of the comb toothportions 131 c is preferably set to 45 μm or smaller.

Because the electrode base portion 132 does not contribute totransmission of light, the width D1 of the electrode base portion 132 inthe X-direction (direction orthogonal to the extending direction of theelectrode base portion 132) is preferably set to a smaller value. Thewidth D1 is preferably set to a value larger than 0 μm and equal to orsmaller than 4 μm. Setting the width D1 larger than 0 μm can increasethe conductivity, whereas setting the width D1 equal to or smaller than4 μm can suppress a decrease in the transmittance. In a case where thewidth D1 is larger than 0 μm and equal to or smaller than 4 μm and wherethe comb tooth protrusion length of the comb tooth portions 131 c is 45μm or smaller, the display area 21 can serve as a high-definition screenof 160 ppi or higher. In a case where the width w1 is 0.5 for example,the width w2 is preferably set to 1 μm or larger to ensure the qualitythroughout the comb tooth protrusion length of the comb tooth portions131 c.

In the liquid crystal display device 1 according to the fourthmodification of the embodiment, the aperture 76 b also includes thelight-blocking part 76 e having a light blocking property in the samelayer as the source electrode 91 or the drain electrode 90. Alight-blocking part 76 e is provided to the pixel substrate 70A. Amaterial of the light-blocking part 76 e is the same as that of thesource electrode 91 or the signal line 25—that is wiring for causing thefirst electrode 31 or the second electrode 32 to work. A light-blockingpart 76 f is provided to the pixel substrate 70A. A material of thelight-blocking part 76 f is the same as that of the scanning line24—that is wiring for causing the first electrode 31 or the secondelectrode 32 to work. Due to this, a forming pattern of thelight-blocking part 76 e or the light-blocking part 76 f has highaccuracy, and does not require additional processes. A position of thelight-blocking part 76 c corresponds to the disclination line dc1described above. The liquid crystal display device 1 according to thefourth modification of the embodiment includes at least one of thelight-blocking part 76 c, the light-blocking part 76 e, and thelight-blocking part 76 f for reducing intensity of light passingtherethrough at a position overlapping with the center of the first combtooth portion 131 c and the center between the adjacent first comb toothportions 131 c in a direction perpendicular to the first substrate. As aresult, the contrast of the whole sub-pixels can be improved. It issufficient that the liquid crystal display device 1 according to theembodiment includes at least one of the light-blocking part 76 c, thelight-blocking part 76 e, and the light-blocking part 76 f illustratedin FIG. 21. As illustrated in FIG. 21, the light-blocking part 76 e andthe light-blocking part 76 f are arranged both at the center of thefirst comb tooth portion 131 c and at the center between the adjacentfirst comb tooth portions 131 c. The arrangement of the light-blockingpart 76 e and the light-blocking part 76 f is not limited thereto. Thelight-blocking part may be arranged at least at any of the center of thefirst comb tooth portion 131 c and the center between the adjacent firstcomb tooth portions 131 c. As exemplified in the arrangement of thelight-blocking part 76 e and the light-blocking part 76 f, thelight-blocking part may be formed on both of the TFT substrate 71serving as the first substrate and the glass substrate 72 serving as thesecond substrate, or formed on any one of the first substrate and thesecond substrate.

As described above, setting the slit pitch p to a smaller value canincrease the response speed. A decrease in the slit pitch p, however,increases the width of the comb tooth portions 131 c in the Y-direction,for example, resulting in an increase in the area that does notcontribute to transmission of light. Even when the liquid crystaldisplay device 1 according to the fourth modification of the embodimenthas an aspect of the fourth modification, the device exhibits the sameadvantage as that of the embodiment.

Evaluation Example

The following describes evaluation results of a first evaluation exampleto a third evaluation example. The present invention is not limited tothese evaluation examples. FIG. 22 is an explanatory diagram forexplaining a relation between the response speed of the pixel and anaverage interval between the disclination lines in a first evaluationexample of the liquid crystal display unit according to the embodiment.In a case where a reference response time Tf is 1 assuming that theaverage interval 1 between adjacent disclination lines dc1 is infinityand voltage is off under the same conditions of an aperture width and acell thickness d of the sub-pixels Vpix in the first evaluation example,simulated are relative values of a response time t when voltage is offwith respect to the reference response time when the average interval 1is each of 2 μm, 3 μm, 5 μm, 10 μm, 20 μm, and 100 μm. FIG. 22illustrates a simulation result. As illustrated in FIG. 22, when theaverage interval 1 is equal to or smaller than 10 μm, the liquid crystaldisplay device 1 can accelerate the response time t when voltage is off.As a result, the liquid crystal display device 1 can accelerate theresponse speed of the liquid crystals.

FIG. 23 is an explanatory diagram for explaining a relation between theresponse speed of the pixel and the average transmission effectiveinterval in a second evaluation example of the liquid crystal displayunit according to the embodiment. In a case where the reference responsetime Tf is 1 assuming that the average transmission effective intervalEm is infinity and voltage is off, simulated are the relative values ofthe response time when voltage is off with respect to the averageinterval reference response time while changing the average transmissioneffective interval Em for respective cases where the average interval 1is each of 3 μm and 100 μm. FIG. 23 illustrates a simulation result. Asillustrated in FIG. 23, when the average transmission effective intervalEm is equal to or smaller than 10 μm, the liquid crystal display device1 can accelerate the response time when voltage is off.

Application Examples

The following describes application examples of the liquid crystaldisplay device 1 explained in the embodiment and the modificationsthereof with reference to FIGS. 24 and 25. FIGS. 24 and 25 are diagramsillustrating an example of an electronic apparatus to which the liquidcrystal display device according to the embodiment is applied. Theliquid crystal display device 1 according to the embodiment isapplicable to electronic apparatuses of all fields, such as carnavigation systems as illustrated in FIG. 24, television apparatuses,digital cameras, notebook personal computers, portable electronicapparatuses including mobile phones as illustrated in FIG. 25, or videocameras. In other words, the liquid crystal display device 1 accordingto the embodiment is applicable to electronic apparatuses of all fieldsthat display video signals received from the outside or video signalsgenerated inside thereof as an image or video. The electronic apparatusincludes a control device 4 (refer to FIG. 1) that supplies videosignals to the liquid crystal display device and controls the operationof the liquid crystal display device.

An electronic apparatus illustrated in FIG. 24 is a car navigationdevice to which the liquid crystal display device 1 according to theembodiment and the modifications thereof is applied. The liquid crystaldisplay device 1 is arranged on a dashboard 300 inside an automobile.Specifically, the liquid crystal display device 1 is arranged on thedashboard 300 and between a driver seat 311 and a passenger seat 312.The liquid crystal display device 1 of the car navigation device isutilized to display navigation, display a music operation screen,reproduce and display a movie, or the like.

An electronic apparatus illustrated in FIG. 25 operates as a mobilecomputer, a multifunctional mobile phone, a mobile computer capable ofmaking a voice call, or a mobile computer capable of performingcommunications to which the liquid crystal display device 1 according tothe embodiment and the modifications thereof is applied. The electronicapparatus is a portable information terminal, which may be called asmartphone or a tablet terminal. The portable information terminalincludes a display unit 562 on the surface of a housing 561, forexample. The display unit 562 includes the liquid crystal display device1 according to the embodiment and the modifications thereof and a touchdetecting function (what is called a touch panel) that can detectexternal proximity objects.

The embodiment is not limited to the above description. The componentsof the above embodiment encompass a component easily conceivable bythose skilled in the art, substantially the same component, and what iscalled an equivalent. The components can be variously omitted, replaced,and modified without departing from the gist of the embodiment.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications can be madewithout departing from the spirit and scope of the present subjectmatter and without diminishing its intended advantages. It is thereforeintended that such changes and modifications be covered by the appendedclaims.

The invention is claimed as follows:
 1. A liquid crystal display devicecomprising: a first substrate; a second substrate arranged to be opposedto the first substrate; a liquid crystal layer arranged between thefirst substrate and the second substrate; a first electrode arrangedbetween the first substrate and the liquid crystal layer; and a secondelectrode arranged at a position opposed to the first electrode, whereinthe first electrode comprises: an electrode base portion extending in afirst direction; and a plurality of comb tooth portions extending in asecond direction different from the first direction and protruding fromthe electrode base portion with a certain distance interposedtherebetween, and at least one of the first substrate and the secondsubstrate includes a light-blocking part that reduces intensity of lightpassing therethrough at a position overlapping with at least one of thecenter of the comb tooth portion and the center between the adjacentcomb tooth portions in a direction perpendicular to the first substrate.2. The liquid crystal display device according to claim 1, wherein thefirst electrode comprises: a plurality of electrode base portionsextending in the first direction; a plurality of first comb toothportions protruding from each of the electrode base portions in a combteeth shape with a certain distance interposed therebetween in the firstdirection and extending in the second direction different from the firstdirection; and a plurality of second comb tooth portions protruding fromeach of the electrode base portions in a comb teeth shape with a certaindistance interposed therebetween in the first direction and extending ina direction opposite to the second direction, and tips of the first combtooth portion and the second comb tooth portion extending from theadjacent electrode base portions are opposed to each other with a gaptherebetween.
 3. The liquid crystal display device according to claim 1,wherein a plurality of pixels each including a plurality of sub-pixelsare arranged in a matrix, and the light-blocking part is arranged in thesame layer as a second light-blocking part having a light blockingproperty that surrounds an aperture of the sub-pixels.
 4. The liquidcrystal display device according to claim 1, wherein a plurality ofpixels each including a plurality of sub-pixels are arranged in amatrix, and the light-blocking part is arranged in the same layer as asecond light-blocking part having a light blocking property that isarranged to be opposed to a signal line or a scanning line.
 5. Theliquid crystal display device according to claim 1, wherein, in a casewhere the light-blocking part is arranged at a position overlapping withthe center between the adjacent comb tooth portions, the width of thelight-blocking part is half or below the width between the adjacent combtooth portions.
 6. The liquid crystal display device according to claim1, wherein, in a case where the light-blocking part is arranged at aposition overlapping with the center of the comb tooth portion, thewidth of the light-blocking part is half or below the width of the combtooth portion.
 7. The liquid crystal display device according to claim1, wherein the light-blocking part is formed on a first substrate side.8. The liquid crystal display device according to claim 1, wherein thelight-blocking part is formed on a second substrate side.
 9. The liquidcrystal display device according to claim 1, wherein an average intervalbetween the light-blocking parts is equal to or smaller than 10 μm. 10.The liquid crystal display device according to claim 1, wherein aplurality of pixels including a plurality of sub-pixels are arranged ina matrix, and the light-blocking part is provided to the firstsubstrate, and a material of the light-blocking part is the same as thatof wiring that causes the first electrode or the second electrode towork.
 11. The liquid crystal display device according to claim 1,wherein left and right sides of at least part of the comb tooth portionsfacing each other in an extending direction thereof are oblique in aline symmetrical manner.
 12. The liquid crystal display device accordingto claim 1, further comprising: a first orientation film and a secondorientation film, wherein one of the first orientation film and thesecond orientation film is subjected to orientation processing in adirection substantially parallel to an extending direction of the combtooth portions.
 13. An electronic apparatus comprising: a liquid crystaldisplay device; and a control device that supplies input signals to theliquid crystal display device, wherein the liquid crystal display devicecomprises: a first substrate; a second substrate arranged to be opposedto the first substrate; a liquid crystal layer arranged between thefirst substrate and the second substrate; a first electrode arrangedbetween the first substrate and the liquid crystal layer; and a secondelectrode arranged at a position opposed to the first electrode, whereinthe first electrode comprises: an electrode base portion extending in afirst direction; and a plurality of comb tooth portions extending in asecond direction different from the first direction and protruding fromthe electrode base portion with a certain distance interposedtherebetween, and at least one of the first substrate and the secondsubstrate includes a light-blocking part that reduces intensity of lightpassing therethrough at a position overlapping with at least one of thecenter of the comb tooth portion and the center between the adjacentcomb tooth portions in a direction perpendicular to the first substrate.